The synthesis of di- and polycyclic ring systems composed of cyclopentane rings has been developed further, and work on several novel systems of this type has been initiated. An improved and simplified technique for replacement of the N-methyl group of morphine, codeine and thebaine by other alkyls has been worked out in cooperation with colleagues in Bangalore, India. Of the resulting N-alkyl-N-nor compounds, the N-alkyl-N-nor-thebaines are new and have potential value as starting material for other new opioids. The structure of a bright red compound encountered during earlier synthetic work on certain dinaphthofurans has been elucidated in cooperation with Dr. Fales, NHLBI. The substance is a derivative of peri-xanthenoxanthene.